Each puppy/dog has its own a unique personality of their own. We have found Males to be more laid back & Females to be more feisty and Alpha in their personality. If you currently have a dog, I would suggest getting a dog of the opposite sex. Dogs of the same sex tend to fight.
One thing we cannot stress enough is the importance of spaying & neutering your dog. Males before 6 months of age and Females after their 1st heat cycle or when your Vet feels is best for your dog.